Aryltin reagents

The ortho-arylation of 2-arylpyridines with aryltin reagents is mediated by Wilkinson s catalyst. This cross-coupling procedure occurs at high temperatures and consequently, the prevention of double phenylation represents a major hurdle, which is often achieved by adding a methyl group to either the pyridine or aryl group (Equations (125) and (126)).1... 

The Sonogashira coupling of halopyridines was also achieved by other means. Resin bound bromopyridine derivatives, for example, underwent smooth coupling with acetylenes as well as with arylboronic acids and aryltin reagents.44 The advantageous effect of microwave irradiation on the coupling of halopyridines and trimethylsilylacetylene was also reported.45... 

Phenylpyridine is arylated by using aryltin reagents such as Ph4Sn in the presence of a rhodium catalyst (Eq. 15) [21]. The use of a halogenated solvent is important for obtaining a satisfactory yield. Although the precise mechanism is not yet clear, it is likely that a cyclometalated intermediate participates. 

A Diels-Alder reaction between methyl tributylstannylpropiolate and substituted butadienes gives good yields of the 1,4-cyclohexadiene, which can be dehydrogenated to the aryltin reagent [132]. 

Like in the case of an aryltin reagent, an interesting example using Diels-Alder reaction has been reported (Scheme 54) [222]. 

Cross-coupling of allyl halides with vinyltin reagents. Allyl halides couple with vinyl- or aryltin reagents in the presence of this catalyst in uniformly high yields (>80%). A wide variety of functional groups is tolerated. The geometry of the double bond in both partners is retained, but the carbon-to-carbon bond is formed with inversion at the allylic position. 

G. Copper-mediated Reaction of Aryltin Reagents as Aryl Donors. 517... 

Aryltin reagents have been used similarly to arylaluminum compounds for the preparation of C-glycosides. Particularly applied to reactions with furanose glycals, Daves, etal.,77>78 carried our the reactions shown in Schemes 2.4.2 and 2.4.3. Utilizing palladium acetate to mediate the couplings between glycals and aryltributyltin compounds, p anomeric selectivity was observed in poor to good yields. 

Scheme 34. Stille coupling of (hetero)aryl halides with (hetero)aryltin reagents Kelly s molecular brake (68, [22]) and nicotelline (69, [124a]) a) Pd(PPh3)4,b) xylene, A...

Kang and co-workers have reported reactions of open-chain vinyl-substituted cyclic carbonates with many stabilized and nonstabilized carbon nucleophiles,heteroatom nucleophiles, hydride equivalent,and vinyl and aryltin reagents. Retention of configuration has been observed for malonate, for thiophenolate, and for the conjugate base of phthalimide. In the absence of nucleophile a proton elimination ensues (Scheme 44). The reaction with iodobenzene produces a reductive ring opening by a variant of the Heck reaction. ... 

A -Benzyloxindoles and Af-benzyldihydroisoquinolinones were synthesized via rhodium(I)-catalyzed [2- -2-1-2] cycloaddition of 1,6-diynes with alkynes, palladium(0)-catalyzed arylative cyclization, and palladium(0)-catalyzed coupling reaction with arylboron or aryltin reagents (Scheme 4.37) [41]. When the reactions were conducted under a CO atmosphere, aryl ketones were obtained through... 

Scheme 4-35. Transmetalation of Grignard or aryltin reagents with...

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